The Seldinger technique is a medical procedure for providing safe access to blood vessels and other anatomic sites. The skin is punctured with a sharp hollow needle. A guidewire is then advanced through the lumen of the needle, and the needle is withdrawn. A small skin incision is made into the skin at the entry site of the wire. A hollow tubular element, such as a sheath, is passed over the guidewire into the target anatomic location, and the guidewire is withdrawn.